Coated fibrous sheet



m purpose has Patented May 2, 1939 UNITED STATES PATENT orrice COATEDFIBROUS SHEET Erich Gcbauer-Fuelnegg, deceased, late of Evanston, 111.,by Marie istratrix, Evanston,

Ge'bauer-Fuelnegg, admin- Ill., and Eugene W. Mofiett, Chicago, llL,assignors,

by mesne assignments,

to Marbo Patents, Inc., a corporation of Delaware V N. Drawing.Application July 31, 1937,

Serial No. 156,750

4 Claims.

wrapper or container. In the present invention V the fibrous base iscoated with athin layer of a compound of rubber formed by reactingrubber either partially or completely with a hydrogen halide by anysuitable process.

It is therefore an object of this invention to provide a fibrous web orsheet base treated with rubber hydrohalide. It is a further object ofthis invention to provide a process for preparing a rubber hydrochloridecoated or impregnated fibrous web or sheet material that is highlyresistant to the penetration of moisture, water, grease or gases; 7

Other and further objects of this invention will be evident from thefoilowing specification and the accompanying claims.

The rubber hydrohalide used in this process 0 may be produced by themethod disclosed in our application Serial No. 703,866, now Patent No.1,980,396. In this process, unvulcanizedrubber, in sheet or comminutedform, is exposed tothe action of a hydrogen halide, such as hydrogen)chloride, either in gaseous form under pressure or inliquefiedcondition. When the reaction is partially or substantiallycomplete, the reaction product is isolated.

By stopping before the reaction is complete, a partially reacted productespecially suitable for use in the present invention may readily beobtained.

It will be understood that other methods may also be used for making therubber hydrohalide, such as passing hydrogen chloride through a solutionof rubber iii-benzene, carbon tetrachloride or other volatile solvent.

V .The rubber hydrochloride preferably should not be entirely reactedwith hydrogen chloride where flexibility is particularly important andgrease resistance is of lesser importance, butwhere grease resistance isof high importance, a substantially saturated rubber hydrochlorideshould be used. Increased" flexibility can then be attained byplasticizing the rubber hydrotion on the invention since the chloride;For ease of plasticization, we prefer the amorphous rubber hydrochlorideobtainable by reacting milled sheet rubber with liquefied hydrogenchloride at 85 C. The substantially saturated amorphous rubber.hydrochloride thus obtained is more soluble in benzenoil hydrocarbonsthan other types of saturated rubber hydrochlorides, and is more readilyheat scalable, thus giving it other advantages for our purposes.However, any rubber hydrochloride sufiiciently resistant to be non tackyis usable.

The rubber hydrochloride is dissolved in any suitable solvent such ascarbon tetrachloride, benzene and its homologues, or ethylenedichloride, preferably to a concentration of 8 to 10%, and in generalbetween 4 and 12% by weight.

A satisfactory coating composition can be made by the above procedure,but is preferable to add a gum or resin to act as a bonding agent. Suchsubstances cause a firmer adherence of the coating to the fibrous baseand may be used in amounts up to 75% of the dry solids contained in thecoating solution. The use of various gums or resins in this manner isalso advantageous since the viscosity of the solution is somewhatreduced by them.

. Various resins, and gums have been found to be compatible with rubberhydrochloride and otherwise satisfactory. These include the soft or'hardArochlors, (chlorinated diphenyls), the soft or hard polycumariones,rosin, copal, phenolaldehydes resins, ester gums, and dammar gum.Various antioxidants may also be added to preserve the rubberhydrochloride if desired.

Waxes such as parafiin wax, bees wax, carnauba wax, 'etc., may be addedin small amounts to the rubber hydrochloride to improve the water andwater vapor resistance.

Plastici'zers may also be added including the softcumarone resins, thesoft chlorinated diphenyls, chlorinated paraflin, fluid ester gums,

dibutyl phthalate, and the like.

The following formula of' a satisfactory coating-composition is notto beconstrued as 'a limitaproportions are not critical, but is to beunderstood as giving desirable proportions which have been found to beoperative. v

- Example Percentage by weight Rubber hydrochloride (amorphous; 29%

chlorine content) 30 to 75 Chlorinated diphenyl to 25' The coatingsolution may comprise a solution by treating paper such as ordinarysulphite paper v with sulfuric acid. The adhesion of rubberhydrochloride to this type of paper is good, and the composite producthas high strength and resistance to water, grease, vapor and oil.

The coating may be applied to one or both sides of the fibrous basematerial in a continuous manner, as by a fountain roll, doctor or thelike, in a tower coater, or in a straight pass an floated type ofcoating machine. In general, the coating will be of a thickness fromapproximately 1% to 10% of the thickness of the base material whenordinary thicknesses of paper are used. Coatings oi .0001" have beenfound satisfactory, particularly when vegetable parchment is used as abase.

This coating also has the great advantage of a being heat sealing. Bythis is meant that when two sheets oi the material are pressed togetherand heated, a secure bondbetween them is formed. This makes it possibleto use paper which has been coated with this composition in wrappingmachines and in the production of bags in a similar manner to waxedpaper. It is preferable to waxed paper, in fact, since when waxed paperis sealed in this manner the bond is much weaker than whenthe materialdisclosed herein is used.

Our coating has the advantage'of being nontacky at ordinary roomtemperatures and resistant to the passage of grease, gas, moisture, andwater, thus making an ideal wrapping material for foodstufls.

Coated .vegetable parchment, for instance, is

admirably suited for making up into bags and other containers for foodproducts, such as frozen foods, fats, butter, coffee andthe like.Laminated material may also be prepared with our composition as theadhesive layer.

Where the term rubber is used herein and in the claims, it will beunderstood to mean rubber, caoutchouc, and rubber-like materials. eithernatural or synthetic in their origin, in-

cluding balata, gutta percha and chicle.

We are aware that numerous details of the process may be varied througha wide rangewithout departing from the principles of this invention, andwe, therefore, do not purpose limiting the patent granted hereonotherwise than necessitated by the prior art.

We claim:

1. A thin, flexible article of manufacture comprising a thin, flexiblesheet of vegetable parchment having a. coating thereon of a compositioncomprising a. rubber hydrochloride and a resin selected from the groupconsisting of chlorinated diphenyls, polycumarones, rosin, copal,phenolaldehyde resins, ester gums and dammar gum.

2. A thin, flexible article of manufac ure ccmprising a thin flexiblesheet of vegetable parchment having a coating thereon of a compositioncomprising a rubber hydrochloride and a phenolaldehyde resin.

3. A thin, flexible article of manufacture comprising a thin flexiblesheet of vegetable .parchment having a coating thereon of a compositioncomprising a rubber hydrochloride and a chlorinated diphenyl.

4. A thin, flexible article of manufacture comprising a thin flexiblesheet of vegetable parchment having a coating thereon of a compositioncomprising a rubber hydrochloride and a polycumarone. I

MARIE GEBAUER-FUELNEGG. Administratria: of the Estate of Erich Gebauer-Fuelnegg, Deceased.

EUGENE W. MOFFETI.

